PHOTOLUMINESCENCE OF GRANULAR CDSE FILMS

We have produced granular films with a high density of CdSe clusters b y a deposition method using a cluster beam. The photoluminescence spec tra of those granular films were measured over the temperature range o f 50-300 K in order to explore quantum size effects and interactions b etween clusters. The results were compared with photoluminescence of a thin film which was made by a conventional vacuum evaporation method. It has been found that the observed blue-shifted broad photoluminesce nce band of the granular film cannot be explained simply by the calcul ation using the effective mass approximation derived by Kayanuma with taking into account the size distribution of CdSe clusters in the film . The discrepancy suggests that the luminescence yield may depend stro ngly on the cluster size. The surface states and connectivity of clust ers which may influence the interaction between clusters in such a gra nular film should be also considered as well as the size-dependent lum inescence yield to explain the temperature dependence of peak energy o f the photoluminescence.